Numerous methods and devices have been described for destruction of the endometrium in order to cause cessation of excessive uterine bleeding or sterilization. Chemical methods have been used and have been uniformly unsuccessful, basically because of the rapid regenerative properties of the tissue to be destroyed. In addition, the chemicals used may be very toxic. Physical methods have fared somewhat better as will be presently described.
In U.S. Pat. No, 3,924,628 Droegemueller et al. describe a method and apparatus for cryogenic destruction of the endometrium utilizing a distending bladder and cryogenic material. This apparatus has had only limited success basically because the procedure is a blind one. Since the blind procedure may produce an incompletely distended or inflated bladder, large areas of the endometrium in such cases are not in adequate contact with the bladder to cause complete destruction of the endometrium. The incomplete destruction of the endometrium allows blood to accumulate within the uterus and produces a painful condition known as hematometra. In addition, perforation of the uterus during blind insertion could cause cryogenic damage to adjacent organs with resultant serious medical complications.
Neuwirth and Bolduc, U.S. Pat. No. 4,949,718, similarly describe a bladder inserted blindly into the uterine cavity with a heating element within the bladder to maintain adequate heat within the unit. The use of the bladder in a blind technique again may not assure contact with the entire endometrial surface. They also describe a 5% dextrose solution used to distend the bladder and an external means to maintain the distending pressure within the bladder. This technique is a blind one and could result in areas of the endometrium being spared, thus yielding results similar to that of Droegemueller et al. In addition, perforation of the uterus by the blind technique could result in thermal injury to adjacent organs.
Other patents that describe thermal methods involving imperfect contact or conformation with the shape of body cavities and also blind approaches are U.S. Pat. Nos. 2,734,508; 2,077,453; 3,369,549; 2,192,768; 2,466,042; and 2,777,445.
The reported successful efforts to effect endometrial destruction have all utilized direct visualization to effect complete destruction of the endometrium. The first successful method was described by Goldrath et al. (M. H. Goldrath, T. A. Fuller, and S. Segal, Laser Photovaporization of the Endometrium for the Treatment of Menorrhagia, American Journal of Obstetrics and Gynecology, 104-14, 1981) using the Neodymium:YAG laser under direct vision through a hysteroscope. Intense amounts of thermal energy are applied through a fiber optic to systematically destroy the endometrial surface. This procedure, although admittedly tedious, has been successful. Similar success has been enjoyed by the use of high frequency coagulating current also utilizing direct vision through a hysteroscope. Both of these methods require considerable skill and there is a potential risk of perforation of the uterus which could cause damage to other organs. In addition, since a large amount of fluid is used to distend the uterus for visualization, this fluid may be absorbed into the circulation and if excessive could cause physical problems.